Gatte is the plural form of gatta, meaning 'female cat'. While 'cat' is a common word, Vasco Rossi's specific use of 'gatte' in this context is quite unique and evocative.
In the song, the narrator is taking Valium to sleep and counts 'le gatte' (the female cats) with a black spot on their snout, in the attics near the sea. This imagery creates a surreal and almost hallucinatory scene, making the word 'gatte' stand out as a key element in conveying the song's mood of detachment and altered reality.